KARACHI, Pakistan – Hundreds of residents angered over a 16-hour power outage rioted in the southern Pakistan city of Karachi overnight, ransacking a KFC restaurant and two banks, police said Thursday.

At least six people were hurt as youths burned tires on roads, stoned passing cars and caused extensive damage to commercial property in the south of the city during two hours of unrest.

Police used tear gas to control the mob, and arrested 13 people, police officer Azad Khan said.

The riot ended when power was restored early Thursday.

The KFC restaurant near an upscale district of the city was badly damaged, and rioters made off with the cash register. Two guards at the restaurant were among those injured in the violence.

Rioters also smashed the glass doors and windows of two local banks but could not break in as they were repelled by police, Khan said. About two dozen vehicles also were damaged.

Less serious unrest broke out in two other districts of this teeming city of about 15 million people, the country's main port and business capital, where anger is focused on the privatized local power utility.

Electricity shortages have struck much of Pakistan just as temperatures top 100 degrees Fahrenheit, forcing businesses to close or throw away perishable products and leaving residents stewing in their homes.